function repeat(str, count) {
// 你的实现
    let res = ''
    if (!str) {
        return res
    }
    if (!count) {
        return res
    }
    for (let i = 0; i < count; i++) {
        res += str
    }
    return res
}

let one = repeat('abc', 3)
let two = repeat('abc', 0)
let three = repeat('', 10)
console.log(one)
console.log(two)
console.log(two)